What are differences between <aside> and <blockquote> tags in HTML5?

If you can remove an <aside> from the page, and the content to which it’s tangential becomes incomplete, then you should not be using <aside>.

If you can remove a <blockquote> from the page, and the content around it is complete even without it, then you should not be using <blockquote>.

So only use <blockquote> to quote external sources that are part of the primary content, not for ‘side’ content that’s decorative or is repeated in the primary content. The two quotes in this very article are legitimate <blockquote> content because without them the content would be incomplete.

Email codedump link for What are differences between &lt;aside&gt; and &lt;blockquote&gt; tags in HTML5?